See that tiny bump on the branch? You’re looking at a mom protecting hundreds of babies. Well, actually, the mama Oak Scale insect (Parthenolecanium quercifex) is dead now, but her exoskeleton is still harboring those little eggs underneath. When those baby Scales hatch around the end of May, the tiny darlings will move out to the oak leaves and begin to SUCK THAT POOR TREE DRY. They sniff out the precious sugar-water flowing through veins in leaves, insert their straw-like mouth parts and drink up. As the year progresses, Scales grow and mate. Mama lays her eggs beneath her and dies, making way for next May’s new generation.
(These are the eggs… um, on my kitchen table. Didn’t realize they’d pop out like that when I lifted the mama Scale off. Oops.)
In the insect’s defense, healthy trees can resist Scale infestations. Some leaves and twigs may fall off – that’s all. But trees that are weakened (by physical damage, drought, chemicals, etc.) can be killed by the insects.
Cool Climate Change research recently found that densities of Oak Scale are up to 13x higher in warm urban areas! (1) Since things are getting toastier here on Earth, we may want to get more familiar with the life & times of the Oak Scale.
1. Meineke EK, Dunn RR, Sexton JO, Frank SD (2013) Urban Warming Drives Insect Pest Abundance on Street Trees. PLoS ONE 8(3): e59687. doi:10.1371/journal.pone.0059687